April, ’18] 
MORRILL: GRASSHOPPER BAITS 
175 
erations a year. During a comparatively cool summer, like that of 
1917, there were probably not more than three generations produced. 
While up to the present time Eupelminus saltator has been of incon¬ 
siderable importance in the natural control of the Hessian fly, it is 
also true that during the time we have had it under observation there 
has been no extensive outbreak of either the Hessian fly or Harmolita. 
It seems probable that when either of these hosts becomes abundant, 
the numbers of the parasite will increase and aid in reducing the num¬ 
bers of this host. In case the alternate host becomes abundant the 
following season, the parasites will then be ready to turn their atten¬ 
tion to it in increased numbers and with considerable effect. It will 
be necessary to keep this parasite under observation for a series of 
years before its real value can be correctly estimated. 
References 
(1) Lindemann, K. 1887. Die Pteromalinen der Hessenfliege. In Soc. Imp. Nat. 
Moscou Bull., vol. I, pp. 190-191. 
(2) Marchal, Paul. 1906. Les Platygasters. In Arch. Zool. Exp. et Gen., IV 
serie, T. IV, p. 507. 
President R. A. Cooley: The next paper is “Grasshopper 
Observations, Experiments and Demonstrations in Arizona, During 
1917,” by Mr. A. W. Morrill. 
EXPERIMENTS WITH GRASSHOPPER BAITS WITH INCI¬ 
DENTAL OBSERVATIONS ON THE HABITS AND DE¬ 
STRUCTIVENESS OF THE DIFFERENTIAL GRASSHOPPER 
(MELANOPLUS DIFFERENT!ALIS) 
By A. W. Morrill, Phoenix , Arizona 
In connection with demonstration work against grasshoppers in 
Arizona during the past season problems were presented which led 
to the series of observations and tests which form the basis of this 
paper. It was at first believed that one or two days’ work would 
give the desired information but the results failed to meet expectations 
in this respect. Although the conclusions which may be drawn from 
these experiments are not as definite as desired, this paper is presented 
in the hope that it may be of some use during the coming season in 
suggesting profitable lines of work to others interested in grasshopper 
control as well as of some direct value as a contribution to our litera¬ 
ture on this subject. The experimental work here reported was 
